1. Field of the Invention
The present invention relates to an ink jet print head that ejects ink or the like to a print medium, a method for manufacturing the ink jet print head, and a printing apparatus.
2. Description of the Related Art
Printing apparatuses using an ink jet printing system of ejecting ink to a print medium for printing have excellent characteristics. These printing apparatuses easily provide a high resolution image, operate silently at a high speed, and are inexpensive, as compared to printing apparatuses based on other systems. However, with the recent significant prevalence of personal computers, digital cameras, and the like, there has been a demand to stabilize the operation of ink jet printing apparatuses or ink jet print heads as image output instruments.
FIG. 15A is a schematic top view showing a conventional ink jet print head disclosed in, for example, Japanese Patent Laid-Open No. 2006-56243 (corresponding to US Patent Publication 2007-242101). FIG. 15B is a partial sectional view showing a part of a side surface of the ink jet print head in FIG. 15A. A flexible board 1502 is bonded to a support member 1504, and a board (hereinafter referred to as a liquid ejection board) 1501 having a plurality of fine nozzles for ink ejection is mounted on the flexible board 1502. The periphery of the liquid ejection board 1501 is sealed with a sealant 1503. The sealant 1503, for example, prevents a side surface of the liquid ejection board 1501 from possible contact with ink, prevents the possible corrosion by ink of lead terminals connecting the flexible board 1502 and the liquid ejection board 1501 together, or prevents the possible breakage of the lead terminals under an external force.
Ink jet printing apparatuses use characteristic print condition recovery means (hereinafter simply referred to as recovery means). With the ink jet printing apparatus, when ink is ejected from ejection ports, fine ink droplets (ink mists) may be generated and attach to an ejection opening array surface of the print head. In another case, dust such as paper dust may attach to the ejection opening array surface. The attachment may prevent ink from being appropriately ejected, hindering improvement of printing quality. Thus, as means for eliminating the causes of inappropriate ejection, recovery means is generally used which wipes the ejection opening array surface of the liquid ejection board using a wiping member made of an elastic material such as rubber (this operation is hereinafter referred to as wiping), to remove the ink droplets, dust, and the like.
Due to the generally small size of the liquid ejection board 1501, for wiping, a plurality of the liquid ejection boards 1501 are commonly wiped using one wiping member. However, during such wiping, ink is likely to collect in a recessed portion 1505 between the liquid ejection boards 1501.
FIG. 16 shows that ink 1601 has been collected in the recessed portion 1505 between the liquid ejection boards 1501. In this case, when a wiping operation is then performed to scrape the thus collected ink 1601 out of the recessed portion, the ink 1601 may disadvantageously stain the ejection port surface, preventing an appropriate printing operation. In another case, the collected ink may fall onto paper during printing.
On the other hand, even when only one liquid ejection board is used, the periphery of the liquid ejection board may be surrounded by a plate so as to prevent the projection of the liquid ejection board. Also in this case, if any recess is present between the board and the plate, ink is likely to be collected in the recess.
To prevent this phenomenon, the recess, in which ink may be collected, may be effectively filled with a sealant 1503 to flatten and seal the area between the liquid ejection boards 1501 or between the liquid ejection board and the plate.
However, if the sealant is filled into the recess to flatten the area of the recess, the following disadvantages may result.
FIGS. 17 and 18 show that internal stresses α and β have been generated in the conventional ink jet print head by the sealant 1503. If the area between the liquid ejection boards 1501 is sealed so as to be flattened, a relatively large amount of sealant 1503 is used. The sealant 1503 selected to adhere well to a plurality of members unavoidably generates a high internal stress after curing or has a large coefficient of linear expansion. The sealant 1503 generating a high internal stress α or having a large coefficient of linear expansion may be expanded or contracted by a variation in temperature during a manufacturing process or in the temperature of an environment in which the product is used. In this case, the sealant 1503 may exert an external force on the liquid ejection board to break the liquid ejection board.
To prevent the possible breakage of the liquid ejection board 1501, the amount of sealant used to seal the periphery of the liquid ejection board 1501 may be reduced to the minimum required value. However, in order to flatten the area of the recess, in which ink may be collected, a relatively large amount of sealant 1503 unavoidably needs to be used as described above. This may disadvantageously result in damage to the liquid ejection board 1501.
If the area between the liquid ejection boards 1501 are sealed with the sealant 1503 so as to be flattened as shown in FIG. 18, the sealant 1503 may contact ink and swell during printing. In this case, the stress β may also occur to peel the sealant 1503 off side surfaces of the liquid ejection boards 1501.
Further features of the present invention will become apparent from the following description of exemplary embodiments (with reference to the attached drawings).